The present invention relates to a heading detecting apparatus in which a heading signal, corresponding to the direction of travel of a moving object such as an automotive vehicle, is generated in response to the signals from a geomagnetic field sensor.
With heading detecting apparatuses heretofore known in the art, any offsets of the earth's magnetic field due to the remanence of a vehicle or the like are compensated for by compensating magnets which are mounted externally on the vehicle.
With this construction, it is necessary to consider a number of other aspects, such as the location, number and intensity of the compensating magnets mounted externally for cancellation of any offsets of the earth's magnetic field due to the remanence of the vehicle thus complicating the compensation, and moreover this compensation must be different for different vehicles due to variations in their geomagnetic field offset characteristics. Further, the signals from the geomagnetic field sensor themselves are sometimes offset making it difficult to accurately detect the direction of the earth's magnetic field.